A chip washer of the type used with recirculation of wash water generally forms part of a fiberboard production line, in which the wood chips are normally delivered to the chip classifier. The washed chips are then delivered to a chip bin on a chip-refining apparatus in which the chips are refined. Such a chip washer will comprise a scrap separator, a chip pump, a screw dewaterer and a water-treating arrangement. The water flow circulates from this latter arrangement, from the screw dewaterer and back to the scrap separator while cleaning the water in the process.
Known systems of this kind use a single tank for both cleaning and buffering the water. One drawback with these known systems is that it is necessary to interrupt the process at given intervals in order to clean the tank and remove settled bottom sludge therefrom. Another drawback is that the water is not cleaned satisfactorily with this type of tank. Furthermore, because of its small volume the buffering capacity, or temporary storage capacity, of the tank is poor.
One object of the present invention is to provide an arrangement for treating a circulating flow of water in a chip washer with which it is unnecessary to stop the process intermittently, but which will enable the process to be effected continuously and with which cleansing and buffering of the water are also improved.